gistfile1.txt

{
  "@context": {
    "sdo": "http://schema.org/",
    "sdo:url": { "@type": "@id" },
    "sdo:image": { "@type": "@id" },
    "sdo:byArtist": { "@type": "@id" },
    "sdo:embedUrl": { "@type": "@id" },
    "sdo:audio": { "@type": "@id" }
  },

  "@type": "sdo:MusicRecording",
  "sdo:name": "Testing Recording at Google",
  "sdo:url": "http://soundcloud.com/adewale-oshineye/testing-recording-at-google",
  "sdo:image": "http://i1.sndcdn.com/avatars-000027061050-bapmul-crop.jpg?5ffe3cd",
  "sdo:duration": "PT00H00M04S",
  "sdo:description": "This description left intentionally blank. ",
  "sdo:byArtist": { 
     "@type": "sdo:MusicGroup",
     "sdo:name": "http://soundcloud.com/adewale-oshiney",
     "sdo:audio": {
       "@type": "AudioObject",
       "sdo:embedUrl": "https://w.soundcloud.com/player/?url=http%3A%2F%2Fapi.soundcloud.com%2Ftracks%2F87135258&show_artwork=true"
     }
   }
}

{
  "@context": "http://schema.org", 
  "@type": "sdo:MusicRecording",
  "name": "Testing Recording at Google",
  "url": "http://soundcloud.com/adewale-oshineye/testing-recording-at-google",
  "image": "http://i1.sndcdn.com/avatars-000027061050-bapmul-crop.jpg?5ffe3cd",
  "duration": "PT00H00M04S",
  "description": "This description left intentionally blank. ",
  "byArtist": { 
     "@type": "sdo:MusicGroup",
     "name": "http://soundcloud.com/adewale-oshiney",
     "audio": {
       "@type": "AudioObject",
       "embedUrl": "https://w.soundcloud.com/player/?url=http%3A%2F%2Fapi.soundcloud.com%2Ftracks%2F87135258&show_artwork=true"
     }
   }
}

If you define "MusicRecording": "sdo:MusicRecording" (and the other types) in the context, you can also remove the remaining prefixes.

{
  "@context": "http://schema.org", 
  "@type": "MusicRecording",
  "name": "Testing Recording at Google",
  "url": "http://soundcloud.com/adewale-oshineye/testing-recording-at-google",
  "image": "http://i1.sndcdn.com/avatars-000027061050-bapmul-crop.jpg?5ffe3cd",
  "duration": "PT00H00M04S",
  "description": "This description left intentionally blank. ",
  "byArtist": { 
     "@type": "MusicGroup",
     "name": "http://soundcloud.com/adewale-oshiney",
     "audio": {
       "@type": "AudioObject",
       "embedUrl": "https://w.soundcloud.com/player/?url=http%3A%2F%2Fapi.soundcloud.com%2Ftracks%2F87135258&show_artwork=true"
     }
   }
}